EP1346746A1 - Medical device for gripping an elongated member - Google Patents

Abstract

A medical device, for gripping an elongated member, comprises a plurality offingers (16) having portions (28) between which the elongated member is to begripped when the fingers are urged together into an engagement position. Eachfinger has a pair of side surfaces (22), each of which is to be urged towards a sidesurface of an adjacent finger when the fingers arc urged into the engagementposition. Adjacent side surfaces are shaped to prevent penetration of the space orslit (19) between two fingers by said elongated member. A single zigzag shape ofthe slit in the region of the head (11) of the vice, and a vice comprising fourfingers and a single material are preferred.

Description

• The present invention relates to the field of medical devices in general, and moreparticularly to methods and devices for the manipulation of elongated members,such as guidewires, during access to animal or human bodily passages such asblood vessels.
• Medical guidewires have a small diameter, making it impractical for a physicianto grip and manipulate such a guidewire directly by hand. This is a majordisadvantage in an emergency where it is critical to the survival of patients thatcatheterisation of branched or convoluted blood vessels be an efficient procedure.The present invention concerns a vice, which is also known as a "torque" device,a "gripping" device, a "steering" device or "migration controller" device, andwhich is used to facilitate the manipulation of small diameter guidewires.
• The gripping means described in the prior art are broadly divided into systemseither using a rubber, or a mechanical mechanism such as the one disclosed in USpatents 5,851,189 and 5,392,778.
• US patent 5,851,189 to Forber discloses a torque device for attaching to andselectively gripping and releasing a guidewire to permit rotational andlongitudinal manipulation of the guidewire and thereby to steer the guidewirethrough the vessels of a patient. The grip of the device over the guidewire isadjustable by means of two interconnected cylinders that can rotate with respect toeach other. The first cylinder is the gripping device comprising a spindle with twofingers straddling the guidewire. The second cylinder is a cap that is rotated withrespect to the first cylinder to force the distal end of the fingers to advance along atapering bore in the cap and to close and grip the guidewire. The Forber device issimple and the guidewire is kept centred between the fingers of the spindlebecause the cap has a cylindrical bore through which the guidewire is threadedand maintained within the axis of the device. Furthermore, in the preferred embodiment of the Forber device, the spindle has only two fingers, so that thedevice can accommodate the full range of guidewire diameters with one singledevice. However, the Forber device has two main disadvantages. Firstly itsgripping ability depends on the action of a spindle with only two fingers, andsecondly, because the cap that maintains the guidewire centred within the spindleis an integral part of the gripping mechanism, manual access to the cap must bepreserved at all times.
• US patent 5,392,778 to Horzewski discloses a similar device consisting of twocylinders that slide with respect to each other, one surrounding the distal part ofthe other. The inner cylinder comprises a multitude of prongs that encircle aguidewire that is threaded through a central passage of the inner cylinder. Theouter cylinder, which comprises an inner ring encircling the prongs, can beadvanced manually with respect to the first cylinder to close the prongs over theguidewire and provide a grip when the device is used to manipulate the guidewire.The Horzewski device has substantially the same disadvantages as the Forberdevice. The prongs are made of a resilient material, permitting the prongs to bendduring compression by the outer cylinder, possibly compromising the grippingability of the device. In addition, manual access to the outer cylinder thatmaintains the guidewire centred within the device has to be preserved.
• One of the major disadvantages of the prior art devices is the possibility, duringintroduction of the guidewire, that it might get caught in the linear slits betweenthe fingers or prongs of the device, causing the guidewire to become entrapped inthe device, which could lead to kinking of the guidewire requiring it to beremoved and replaced. Time might therefore be wasted, particularly in a situationwhere it is critical for the survival of a patient that a guidewire or other elongatedmember be introduced promptly in the vascular system.
• The present invention seeks to provide a device that can easily grip an elongatedmember such as a guidewire, that is self-centring, meaning that an elongated member could be maintained in the centre of the device without the help of anyother component, that has an excellent ability to grip, that is capable ofaccommodating a wide range of elongated member's diameters, and that is yetsimple and inexpensive to manufacture.
• The foregoing problems are solved and a technical advance is achieved in amedical device, such as a vice for gripping an elongated member, the vicecomprising a plurality of fingers encircling the elongated member when it isthreaded through the central passage of the device. When the fingers are urgedtogether into an engagement position, a portion of each finger grips the elongatedmember. Each finger comprises a pair of side surfaces, each of which is to beurged towards a side surface of an adjacent finger. Adjacent side surfaces areshaped with respect to each other, resulting in slits that are not straight andthereby preventing entrapment of the elongated member between the side surfacesof the fingers of the vice.
• A vice formed in accordance with the present invention has a number ofadvantages. Since the side surfaces of adjacent fingers are shaped, and thereforethe space or slit between the fingers is not straight, the elongated member isprevented to penetrate into the spaces or slits between the fingers, thereforeavoiding one of the disadvantages of prior art devices where a guidewire couldbecome entrapped between fingers or prongs having a straight space betweenthem. A guidewire is, despite its high flexibility, to be regarded as straight onportions as short as the shaped part of the vice. The adjacent side surfaces of apair of adjacent fingers could be shaped with all kinds of recesses andsubstantially complementary protrusions, thereby preventing penetration of theslits by a substantially straight elongated member. Kinking of the guidewire isthus totally avoided by the present invention. A further advantage of the vice isthe self-centring ability: because the elongated member is unable to becomeentrapped in the slits between fingers, it is therefore kept in the central passage ofthe vice without the use of any other component of the vice. A device according to the present invention will accommodate a wide range of diameters and/or shapesof the elongated member, since even an elongated member having a diametermuch smaller than the distance between the side surfaces of adjacent fingerswould not be able to penetrate a slit that is not straight.
• Embodiments of the present invention will now be described by way of exampleand with reference to the accompanying drawings in which:
• Figure 1 is a three-dimensional view illustrating the preferred embodiment of thevice in accordance with the present invention; and
• Figure 2 is a lateral view of the vice of Figure 1 in accordance with the presentinvention; and
• Figure 3 is an end on view of the distal end of the vice of Figure 1 in accordancewith the present invention; and
• Figure 4 illustrates a longitudinal cross-sectional view of the vice at level A-A ofFigure 3, in accordance with the present invention; and
• Figure 5 is a three-dimensional view illustrating the inner side of a finger of thevice, in accordance with the present invention; and
• Figure 6 is a three-dimensional view illustrating a second embodiment of the vicein accordance with the present invention; and
• Figure 7 is a three-dimensional view illustrating a third embodiment of the vice inaccordance with the present invention; and
• Figure 8 is a longitudinal cross-sectional view of a vice in accordance with thepresent invention illustrating features of adjacent side surfaces of adjacent fingers.
• Figures 1 to 5 illustrate the preferred embodiment of the vice, which comprisesthree main parts: abase10, aneck12 and ahead11.Base10 is preferablycylindrical and located in the proximal portion of the device. Neck12 ispreferably cylindrical and located betweenbase10 andhead11.Head11, whichis also preferably cylindrical, is located in the distal portion of the device.Proximalintermediate part13 extends betweenneck12 andbase10, and distalintermediate part14 extends betweenneck12 andhead11. The proximalintermediate part13, which can have any shape, preferably tapers from thelargerdiameter base10 to thesmaller diameter neck12. Alternatively, the diameter ofneck12 can be made equal to or larger than the diameter ofhead11 and/orbase10. The distalintermediate part14 has preferably a conical shape, but can haveany other shape.Distal part15 of the vice is preferably conical and has a diameterthat decreases towards thedistal end18 of the device. Alternatively,distal part15can have any shape and be smaller than, equal to or larger thanhead11.
• A vice is used for gripping elongated members such as a guidewire. The elongatedmember is threaded within acentral passage21 of the vice, as illustrated in Figure4. In Figures 3 to 5, the distal opening of thecentral passage21 is illustrated as anenlarged distalconical bore31, located within thedistal part15 of the vice, inorder to facilitate the introduction of an elongated member through the distalopening of the central passage. It should be noted, however, that it is preferable tointroduce the elongated member into the vice through the proximalconical bore26. The part of the vice distal tobase10 comprises at least two fingers, preferablythree fingers, and most preferably fourfingers16, each extending longitudinallyfrombase10 and each having a freedistal end18. It is to be noted that although athree-finger device provides a self-centring mechanism for the elongated member,the preferred embodiment of the present invention comprises four fingers becauseof the ease of manufacturing such a device. The gripping action of the device isachieved when thefingers16 are urged together into an engagement position withthe elongated member. The space between twoadjacent side surfaces22 of twoadjacent fingers16 delimits aslit19 having a shape that is not straight, forpreventing access of the elongated member therethrough. The number of slitsbetweenfingers16 depends on the total number of fingers comprised in thedevice; for example, a vice with four fingers has four slits. Theproximal part20ofslit19, located at the level of proximalintermediate part13, has a shape that isfor example triangular, as illustrated in Figure 1, or rounded as illustrated inFigures 6 and 7.Proximal part20 can also have any other shape. Becauseelongated members are prone to become entrapped between the fingers of a vicehaving straight slits, the vice of the present invention has slits that are not straightin shape. Features of theside surfaces22, such as forexample protuberance23and recess24, are responsible for creating non-straight slits. The parts of the slitwhere the side surface features are located constitute the non-straight part of theslit. This non-straight part can extend over the entire length of the slit orpreferably only over a fraction of its length. The non-straight part of the slit ispreferably located in the distal portion of the vice, more preferably at the level ofthe distalintermediate part14 andhead11, and most preferably at the level of thehead11 of the vice, as a single non-straight part. A single slit can also havemultiple non-straight parts that are not contiguous. Figure 6 is an example of avice wherein the non-straight part of the slit is located in both the distalintermediate part14 and thehead11. A vice formed with non-straight slits, inaccordance with the present invention, makes it impossible for an elongatedmember to become entrapped between the fingers of the device. An exemplaryfeature of theside surface22 consists of aprotuberance23 preferably located atthe level ofhead11 of oneside surface22 of afinger16, which substantiallycomplements arecess24 on theadjacent side surface22 of anadjacent finger16,when the fingers are urged together in an engagement position. In the preferredembodiment, which comprises four fingers, theslits19 that are diametricallyopposed are identical. One of the main advantages of such an embodiment is thatthe manufacturing process is simplified and efficient, as it is possible, for exampleduring electro-discharge machinery cutting, to cut in a single pass a pair of shapedand diametrically opposed slits. A second cut creates the other pair of shaped opposed slits, which have either an identical or a different shape than that of theformer pair of slits. Therefore, the fingers of the vice of the preferred embodimentare all different. If opposing slits are not cut simultaneously, i.e. four cuts are thennecessary to create four slits. In the latter case, two different pairs of identicalfingers or four identical fingers are created. Alternative devices according to thepresent invention comprise fingers with identical or dissimilar side surfaces. Forexample, a finger can have a protuberance or a recess on both of its side surfaces.A protuberance or recess of one side surface may be offset longitudinally withrespect to the protuberance or recess of the other side surface of the same finger.Further devices in accordance with the present invention comprise fingers havingfeatures on adjacent side surfaces of adjacent fingers that are not complementary.Figure 8 illustrates one non-limitative example of non-complementary features.Producing a vice with complementary features of adjacent side surfaces has amajor advantage with respect to ease of manufacture compared to production of avice with non-complementary features, since in the former case, cutting of a slitresults automatically in the appropriate shaping of the adjacent complementaryfeatures. This is not the case for side surfaces with non-complementary features,where multiple cuts are needed to create a slit.
• Figure 4 illustrates a longitudinal cross-scctional view of the vice of Figure 3 atlevel A-A.Central passage21 has three portions: a proximal portion thatcorresponds to base10, an intermediate portion that corresponds to proximalintermediate part13 andneck12, and a distal portion that corresponds to distalintermediate part14,head11 anddistal part15. The proximal portion of thecentral passage21 has aproximal bore26, that is preferably conical, to facilitateintroduction of an elongated member in a proximal to distal direction. The distalportion ofpassage21 within thedistal part15 of the vice is preferably conical toallow for introduction of an elongated member in a distal to proximal direction.The proximal conical bore26 has sloping edges, preferably at an angle of about15° with respect to the longitudinal axis of the vice.Central passage21, withinneck12 of the vice, is preferably cylindrical and has a diameter that is slightly larger than the diameter of thecentral passage21 withinhead11. Inner bore27, atthe junction of intermediate portion and distal portions ofcentral passage21, ispreferably conical and has sloping edges preferably at an angle of about 15° withrespect to the longitudinal axis of the vice. Distal inner bore27 at the level of thedistal part15 of the vice is enlarged in a preferably conical shape with slopingedges preferably at an angle of about 30° with respect to the longitudinal axis ofthe vice.Passage21 can be formed to have different shapes than the ones depictedabove. For example and without limitations,passage21 can have a transversesection that is square or elliptical in one or several portions ofcentral passage21.The edges of the side surfaces22 atdistal end18 are optionally chamfered.
• Figures 5 illustrates the inner side of a segment of the vice comprising anexemplary finger16 and part of the base10 from whichfinger16 extends. The cutout view of the inner side of thecentral passage21 illustrates the proximal portionofcentral passage21 having preferably aconical bore26, continued distally byinner bore27 of the intermediate portion ofcentral passage21 having preferably acylindrical bore, in turn continued distally by the distal portion ofcentral passage21 which is delimited by theportion28 offinger16. The diameter of the distalportion ofcentral passage21, within the distalintermediate part14 andhead11, iscritical to determine the maximum diameter of the elongated member that can beused with such a device. Because of the gripping action that is caused by urgingtogether the fingers of the vice into an engagement position, the area of maximumgrip, in the case of an elongated member that has the same diameter as the criticaldistal portion ofcentral passage21, occurs between pointA and pointB as shownin Figure 4. When the elongated member has a diameter inferior to the diameter ofthe distal portion ofcentral passage21, the maximum grip on the elongatedmember, when the fingers are in the engagement position, occurs atA. Dependingon the amount of external force that is applied to the outer surface of the fingers atthe engagement position, and depending on the material of which the fingers aremade, the length ofportion28 that contacts the elongated member extends frompointA to a point betweenA andB. Even for an elongated member having a diameter inferior to the diameter of the critical distal portion ofcentral passage21,the entire distanceA toB contacts the elongated member when the external forceis sufficiently high and/or the material of which the fingers are made issufficiently flexible. Referring back to Figure 5, theportion28 is interrupted byrecess24. Alternatively, it is contemplated thatprotuberance23 andcomplementary recess24 have a transverse dimension that is less than thetransverse dimension of theside surface22 offinger16 at that level, to allow for acontinuous portion28. It is also contemplated thatportion28, which is linear inthe preferred embodiment, be shaped to improve gripping of the elongatedmember.
• Figure 6 depicts an alternative illustrative embodiment of the present inventionwherein eachfinger16 comprisesseveral protuberances23 and recesses24 ononeside surface22 of a finger, to matchcomplementary recesses24 andprotuberances23 of an adjacent side surface, when thefingers16 are urgedtogether in an engagement position. The space so delimited between adjacent sidesurfaces has a double zigzag shape. It is to be understood that the shape ofprotuberances23 and recesses24 can vary to include, for example, hemispherical,spheroidal, cubical or other protuberances and respective complementary recesses.Moreover, although the protuberances and recesses are preferably located in thedistalintermediate part14 andhead11 of the vice, it is also within the scope ofthe present invention to form vices having protuberances and recesses which arelocated anywhere along the side surfaces22 of each finger to form slits havingeither a single non-straight part or multiple non-straight parts that not contiguous.
• In another embodiment of the present invention illustrated in Figure 7, the fingersare shaped to create slits that have a helical shape in thedistal part15,head11and distalintermediate part14 of the vice, thus creating anon-straight slit19which prevents elongated members to becoming entrapped betweenfingers16 ofthe vice, when thefingers16 are urged together in an engagement position.
• The materials and methods of construction and the dimensions of the device arenot essential and may vary. The material of which the vices are made ispreferably, and not limited to, one of brass, stainless steel, copper, beryllium-copperalloy, or a polymer such as cellulose esters, polyesters, copolyesters,copolyester ethers (COPE) and polyethylene. Although it is preferable to use asingle material to construct the vice in accordance of the present invention, it iswithin the scope of the present invention to construct vices either with acombination of materials, different parts of the vice being constructed fromdifferent materials, or with a mixture of at least two of the materials cited above.Furthermore, it is also to be understood that the vice of the present invention canbe constructed for example from one single piece, or from several piecesconstructed separately and subsequently joined, for example by pressing, bonding,welding or attaching the parts together in any other suitable way. Methods ofmanufacturing the metallic vices of the present invention include for examplemilling, electro-discharge machinery cutting, injection moulding or lathe turning.Alternatively, when for example injection moulding of a liquid crystal polymer isused, the device of the present invention is conveniently made from a number ofpieces that are preferably identical, such as the piece illustrated in Figure 5, andthat are subsequently joined to form the vice of the present invention. Theinjection moulding method of manufacture, by decreasing dramatically theproduction costs of the device, is well suited for industrial production of thepresent device. The dimensions of the vice are not essential and are given belowsolely as examples applying to the illustrative embodiments of the presentinvention.

  Parameters	Approximate values in mm
  Total length of the vice	12.50
  Length ofbase10	3.50
  Length of [base10 + neck12]	7.90
  Diameter ofbase10	3.20
  Depth ofrecess24	0.90
  Length ofdistal part15	0.53
  Width ofslit19	0.60

• For convenience, the device of the present invention has only been described inthe context of a medical use, but it should be kept in mind that the vice depictedabove could also be used, for example, as a component of drill chucks or ofmechanical pencils. For that reason, the dimensions, materials and methods ofmanufacture cited above are merely examples that should not be considered aslimiting features of the present invention.

Claims (9)

1. A medical device for gripping an elongated member, wherein the devicecomprises a plurality of fingers, wherein the fingers have portions betweenwhich the elongated member is to be gripped when the fingers are urgedtogether into an engagement position, wherein each finger has a pair of sidesurfaces each of which is to be urged towards a side surface of an adjacentfinger when the fingers are urged into the engagement position, and whereinadjacent side surfaces are shaped with respect to one another to preventpenetration therebetween by the said elongated member.
2. A device as claimed in claim 1,characterised in that adjacent side surfaceshave shapes with respect to one another that are not complementary.
3. A device as claimed in claim 1,characterised in that adjacent side surfaceshave shapes with respect to one another that are complementary.
4. A device as claimed in claim 1, 2 or 3,characterised in that adjacent sidesurfaces of two fingers have shapes with respect to one another that areidentical to the shapes of at least one other pair of adjacent side surfaces.
5. A device as claimed in claim 1, 2 or 3,characterised in that the shapes ofadjacent side surfaces with respect to one another are different in every pair ofside surfaces.
6. A device as claimed in any of the preceding claims,characterised in that thespace between adjacent side surfaces of at least one pair has a single zigzagshape.
7. A device as claimed in any of the preceding claims,characterised in that thespace between adjacent side surfaces of at least one pair has a double zigzagshape.
8. A device as claimed in any of the preceding claims,characterised in that thespace between adjacent side surfaces of at least one pair has a helical shape.
9. A method of gripping an elongated member by clamping it within a device inwhich adjacent fingers are shaped to prevent penetration of the elongatedmember therebetween.

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